Lapping machine



July 29, 1969 s, BQETTCHER ET AL 3,457,682

LAPPING MACHINE Filed Nov. 25, 1966 2 Sheets-Sheet 1 g) Iva/677i?) rs 52 92267712. Bo art/L87;

James/V Mm,

July 29, 1969 s. A. BOETTCHER ET 3,457,532

LAPPING MACHINE Filed Nuv. 25. 1966 2 Sheets-Sheet 2 United States Patent F 3,457,682 LAPPING MACHINE Stephen A. Boettcher, Deer-field, and James N. Farley, Palatine, 111., assignors to Speerlfam Corporation, Slrokie, 111., a corporation of Illinois Filed Nov. 25, 1 66, Ser. No. 597,114 Int. Cl. B24!) 5/00 US. Cl. 51-129 9 Claims ABSTRACT OF THE DISCLOSURE A carrier ring concentric of a lapping disc adjacent the outer periphery thereof; means on the carrier ring and engageable by retaining members for restraining rotation of the latter about the axis of the lapping disc relative to the carrier ring; and means for selectively rotating the carrier ring about the axis of the lapping disc for accommodating progressive rotation of the retaining members about the axis of the lapping disc in the direction of rotation of the carrier ring.

Our present invention relates to a lapping machine having incorporated therewith apparatus adapted to facilitate loading and unloading of work pieces.

In general, a lapping machine of the type contemplated herein comprises a single lapping disc, which is rotatably driven about a vertical axis, and on which retaining and truing rings rest. These rings are free to rotate about their own axes, but are restrained against rotation about the axis of the lapping disc. The rings thus serve to hold work pieces within them against movement with the lapping disc and to wear the lapping surface for maintaining it in planar condition. Between cycles of lapping, lapped work pieces are removed from the retaining rings and work pieces to be lapped are loaded into the rings. Because the retaining rings are maintained at fixed circumferential locations, the operator must walk around the machine while unloading and loading the retaining rings. This procedure is inconvenient and time consuming.

It is an object of our present invention to provide a lapping machine wherein all of the retaining rings may be successively unloaded and loaded at a single position about the machine.

It is another object of our present invention to provide a lapping machine wherein the retaining rings as a group are controllably and progressively rotated about the axis of the lapping disc so that an operator standing at any given position may successively unload and load the rings as they are moved in front of him.

It is a further object of our present invention to provide a lapping machine wherein each retaining ring is controllably and progressively rotated about the axis of the lapping disc 360" in approximately the period of time required to completely lap the work pieces therein.

Now in order to acquaint those skilled in the art with the manner of constructing and using lapping machines in accordance with the principles of our present invention, we shall describe in connection with the accompanying drawings a preferred embodiment of our invention.

In the drawings:

FIGURE 1 is a plan view of a lapping machine incorporating the principles of our present invention;

FIGURE 2 is a fragmentary sectional View, taken sub- 3,457,682 Patented July 29, 1969 ice stantially along the line 22 in FIGURE 1, looking in the direction indicated by the arrows;

FIGURE 3 is an elevational view of one side of the lapping machine of FIGURE 1, looking in the direction indicated by the arrow 3 in FIGURE 1; and

FIGURE 4 is a foreshortened elevational view of another side of the lapping machine of FIGURE 1, looking in the direction indicated by the arrow 4 in FIGURE 1.

Referring now to the drawings, there is indicated generally by the reference numeral 10 a lapping machine having incorporated therewith apparatus of our present invention which is adapted to facilitate loading and unloading of work pieces. The lapping machine 10 includes a framework with a tubular base or housing 12 which provides support for a horizontal lapping disc 14. By way of illustration, the lapping disc 14 may be of one-piece constructionhaving a central well-bore 16, a horizontal lapping surface 18, and a plurality of radial slots 20 for conveying across the disc abrasive and carrier mixture used in the lapping operation. Selective rotation of the lapping disc 14 about a vertical axis is effected by drive means (not shown) mounted within the housing 12 and having a suitable output shaft connected to the underside of the lapping disc 14. For purposes of the present disclosure, rotation of the lapping disc 14 is presumed to be counterclockwise.

Resting on the lapping surface 18 are a plurality of retaining members 22 in the form of retaining and truing rings. These rings, which number four in the embodiment of our invention disclosed, are adapted to confine therein work pieces 24. Mounted at the center of the lapping disc 14 is an idler wheel 26 which is engaged by the adjacent sides of the retaining rings 22. A carrier ring 28 is arranged concentrically of the lapping disc 14 adjacent the outer periphery thereof. The carrier ring '28 is formed with radially inwardly directed flange portions 30 in which are rotatably mounted roller stops 32 circumferentially spaced apart. The roller stops 32 are engageable by the sides of the respective retaining rings and serve as means for restraining rotation of the rings about the axis of the lapping disc 14 relative to the carrier ring 28. The carrier ring 28 is rotatably supported at its outer periphery by a plurality of circumferentially spaced idler rolls 34 mounted on the framework 12. Also, the outer periphery of the carrier ring 28 is provided with an annular radial groove 36 across which is disposed a plurality of circumferentially spaced axial pins 38 that serve as external gear tee h means.

Mounted on the side of the framework 12 is a vertical plate 49 which supports an electric motor 42, a speed reducer 44 and a horizontally disposed pinion 46. The power driven pinion means 46 projects through an opening in the vertical plate 40 and meshes with the external gear teeth means 38 of the carrier ring 28 whereby the latter may be selectively rotated in a manner and for a purpose to be presently described. For control purposes, a micro switch 48 is mounted on the inboard side of the plate 46 immediately above the carrier ring 28. The micro switch 48 has an actuating plunger 50 that is engageable by vertically extending lugs 52 suitably secured in the carrier ring 28 and circumferentially spaced 90 apart. Mounted on the framework 12 on the side opposite the vertical plate 40 is a conventional control box 54.

During the lapping operation, the lapping disc 14 is rotated, and a freely flowing mixture of abrasive particles and an oil carrier is fed to the disc 14 in a conventional manner. A thin film of this abrasive mixture covers the lapping surface 18, and the retaining .and truing rings 22 and the work pieces 24 ride on such film. Sometimes weight plates (not shown) are disposed within the retaining rings 22 over the work pieces 24. While the weight plates imposed a downward force or pressure on the work pieces 24 for increasing the rate of lapping of the latter, the retaining and truing rings 22 rotate about their own axes whereby to dress the lapping surface 18 for maintenance of its planar condition. Often weight plates are not used as the weight of the work pieces is sufficient to accommodate lapping.

As the lapping disc 14 is rotated, the electric motor 42 is energized and rotation thereby of the pinion 46 serves to rotate slowly the carrier ring 28 in the direction of rotation of the lapping disc 14. Upon completion of rotation of the carrier ring 28 through 90, one of the trip lugs 52 engages the actuating plunger 50 of the micro switch 48 for opening the same whereupon rotation of the lapping disc 14 and carrier ring 28 is interrupted. After a short dwell period, which may be controlled by a suitable timing device, the lapping disc and carrier ring are again rotated until the next trip lug 52 opens the micro switch 48. Following another short dwell period, the lapping disc and carrier ring are still again rotated until the successive trip lug 52 opens the micro switch 48. In this manner, the carrier ring is rotated in steps or stages of 90 interrupted by brief dwell eriods.

While the roller stops 32 rotate with the carrier ring 28 about the axis thereof, the retaining rings 22, as a result of friction forces developed between the lap surface and the rings, are indexed as a group about the axis of the lapping disc at the same rate as the carrier ring 28. In this respect, the carrier ring 28, and correspondingly the retaining rings and work pieces therein, are indexed 90 in approximately one-quarter or less of the period of time required to lap the work pieces. Thus, as each retaining ring progresses 360 slowly around the lapping disc, the work pieces therein are completely lapped. By controllably and progressively rotating the retaining rings as a group about the axis of the lapping disc, an operator can stand at any given position, for example adjacent the control box 54, and unload and load the rings as they are moved in front of him. In this connection, it is during the dwell periods that the operator removes lapped work pieces from the ring momentarily stationed in front of him and reloads that ring with work pieces to be lapped. The described operational arrangement enables the operator to progressively keep the lapping machine fully loaded at all times without moving around the machine.

In the operation of the above described lapping machine, progression of the truing rings through each 90 stage of rotation about the axis of the lapping disc may be either continuous or intermittent. Moreover, if desired, the truing rings and work pieces therein could be moved continuously about the lapping disc rather than in steps or stages of 90 interrupted by brief dwell periods as described. In these circumstances, the micro switch 48 would be inactivated, and unloading and loading of the rings would be carried out while the lapping disc and carrier ring were in continuous rotation. Although it is contemplated that the carrier ring 28 normally would be rotated in the direction of rotation of the lapping disc 14, the carrier ring could be rotated in the opposite direction. In this case, the motor 42, speed reducer 44 and pinion 46 serve as a driving, rather than a braking, system during indexing of the rings 22 as a group about the axis of the lapping disc. Finally, although four retaining rings 22 are normally used, it will be appreciated that the number of rings employed may be increased or decreased as desired. In the latter circumstances, the number, location and spacing of the roller stops 32 and trip lugs 52 would be subject to change as may be required.

While We have shown and described what We believe to be .a preferred embodiment of our present invention, it will be understood by those skilled in the art that various rearrangements and modifications may be made therein without departing from the spirit and scope of our invention.

We claim:

1. For use with a lapping machine having a. framework, a lapping disc rotatably mounted about a vertical axis on the framework and having a horizontal planar lapping surface, and means for rotating the lapping disc, the combination of at least one retaining member resting on the lapping surface and being rotatable about its own axis, a carrier ring concentric of the lapping disc adjacent the outer periphery thereof, means rotatably supporting said carrier ring relative to the framework, means on said carrier ring and engageable by said retaining member for restraining rotation of the latter about the axis of the lapping disc relative to said carrier ring, and said carrier ring bein selectively rotatable about the axis of the lapping disc whereupon said retaining member is progressively rotated about the axis of the lapping disc in the direction of rotation of said carrier ring.

2. The combination of claim 1 including means supported by the framework and having engagement with said carrier ring for selectively rotating said carrier ring.

3. For use with a lapping machine having a framework, a lapping disc rotatably mounted about a vertical axis on the framework and having a horizontal planar lapping surface, and means for rotating the lapping disc, the com bination of at least one retaining member resting on the lapping surface and being rotatable about its own axis, a carrier ring rotatably supported relative to the framework concentric of the lapping disc adjacent the outer periphery thereof, means on said carrier ring and engageable by said retaining member for restraining rotation of the latter about the axis of the lapping disc relative to said carrier ring, said carrier ring being provided with external gear teeth means, and power-driven pinion means meshing with said external gear teeth means for selectively rotating said carrier ring about the axis of the lapping disc whereupon said retaining member is progressively rotated about the axis of the lapping disc in the direction of rotation of said carrier ring.

4. The combination of claim 1 wherein said retaining member is a retaining and truing ring, and said means on said carrier ring is a roller stop.

5. The combination of claim 1 wherein said means rotatably supporting said carrier ring includes a plurality of circumferentially spaced idler rolls mounted on the framework.

6. The combination of claim 1 including a plurality of retaining members resting on the lapping surface and being rotatable about their own axes, a plurality of roller stops on said carrier ring and each being engageable by one of said retaining members for restraining rotation of the latter about the axis of the lapping disc relative to said carrier ring, and means for selectively rotating said carrier ring about the axis of the lapping disc whereupon said retaining members are progressively rotated as a group about the axis of the lapping disc.

7. For use with a lapping machine having a framework, a lapping disc rotatably mounted about a vertical axis on the framework and having a horizontal planar lapping surface, and means for rotating the lapping disc, the combination of a plurality of retaining and truing rings resting on the lapping surface and being rotatable about their own axes, a. carrier ring rotatably supported relative to the framework concentric of the lapping disc adjacent the outer periphery thereof, a plurality of roller stops on said carrier ring and each being engageable by one of said retaining rings for restraining rotation of the latter about the axis of the lapping disc relative to said carrier ring, and means for selectively rotating said carrier ring about the axis of the lapping disc in steps of 90 interrupted by brief dwell periods whereupon said retaining rings are controllably and progressively rotated as a group about the axis of the lapping disc.

8. The combination of claim 7 including a plurality of circumferentially spaced idler rolls mounted on the framework for rotatably supporting said carrier ring.

9. The combination of claim 8 wherein said carrier ring is provided with external gear teeth means, and powerdriven pinion means meshes with said external gear teeth means for selectively rotating said carrier ring.

References Cited UNITED STATES PATENTS ROBERT C. RIORDON, Primary Examiner D. G. KELLY, Assistant Examiner 

